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TypeScript for Beginners

Why TypeScript
Quiz — TypeScript and JavaScript
Running TypeScript
Compile errors
Quiz — a string instead of a number
Types vanish at compile time
Quiz — an error and the JavaScript file

Type annotations
Type inference
Quiz — the result type
Parameters without types
Quiz — when to write a type
let, const and literal types
Quiz — let and const
const and mutable objects
Quiz — const and let

Primitive types
Quiz — primitive types
The any type
Quiz — any at run time
The unknown type
Quiz — unknown
void and never
Quiz — void and the basic types

Union types
Quiz — a shared method
null and undefined in unions
Quiz — the type after ??
Literal types
Quiz — let and a literal type
Enums
Quiz — enum values

Object types
Type aliases
Quiz — a missing property
Optional properties
Quiz — an optional property
Read-only properties
Quiz — which line fails

Array types
Quiz — push of the wrong type
Read-only arrays
Tuples
Quiz — array or tuple
as const
Quiz — the type with as const

Narrowing with typeof
Quiz — the type after return
Null checks and equality
Quiz — zero in a condition
The in and instanceof checks
Quiz — the in operator
Discriminated unions
Quiz — a discriminated union
Exhaustiveness with never
Quiz — a forgotten case
User-defined type guards
Quiz — a wrong check

Interfaces
Quiz — an interface
Extending and intersecting
Quiz — | and &
Structural typing
Quiz — shape, not name
Excess properties in a literal
Quiz — a literal and a variable
Index signatures
Quiz — a missing key
type or interface
Quiz — two interfaces of one name

Parameters and the result
Quiz — calling a function
Optional, default and rest parameters
Quiz — ? or a default value
Function types
Quiz — function types and void
Callbacks and contextual typing
Quiz — a callback with one parameter
Function overloads
Quiz — an overload and a union

Fields and the constructor
Quiz — a field with no value
public, private and # fields
Quiz — private at run time
readonly and parameter properties
Quiz — parameter properties
get, set and static
Quiz — static
Inheritance
Quiz — an overridden method
abstract and implements
Quiz — implements and extends

Generic functions
Quiz — why generics
How T is inferred
Quiz — T for two calls
Constraints with extends
Quiz — a constraint
Generic types
Quiz — Pair<number>
Generic classes
Quiz — the type from pop

keyof and indexed access
Quiz — keyof
typeof in types
Quiz — a type from an array
Partial, Required and Readonly
Quiz — Partial and Required
Pick, Omit and Record
Quiz — Omit and Record

Promise<T> and async
Quiz — an async function's type
Promise.all and callbacks
Quiz — callback or promise
The error in catch is unknown
Quiz — e.message
Data from outside
Quiz — why types don't check a response
Assertions: as and !
Quiz — as at run time

Modules
Quiz — a file with no import
import type
Quiz — what is left of import type
tsconfig.json
Quiz — compilation
.d.ts files and @types
Quiz — @types packages
An order model: putting it together
Quiz — the order model

Courses/TypeScript for Beginners

Quiz · Arrays and tuples · lesson 5 of 7

Quiz — array or tuple

Which type does TypeScript infer for pair?

TypeScript

const pair = ["Аня", 30];

← BackTuples Next →as const

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